Attackers behind the highly successful Locky and Bart ransomware campaigns have returned with a new creation: A malicious file-encrypting program called Jaff that asks victims for payments of around $3,700.

Like Locky and Bart, Jaff is distributed via malicious spam emails sent by the Necurs botnet, according to researchers from Malwarebytes. Necurs first appeared in 2012 and is one of the largest and longest-running botnets around today.

According to an April analysis by researchers from IBM Security, Necurs is made up of about 6 million infected computers and is capable of sending batches of millions of emails at a time. It is also indirectly responsible for a large percentage of the world's cybercrime because it's the main distribution channel for some of the worst banking Trojan and ransomware programs.

The Tuesday updates for Internet Explorer and Microsoft Edge force those browsers to flag SSL/TLS certificates signed with the aging SHA-1 hashing function as insecure. The move follows similar actions by Google Chrome and Mozilla Firefox earlier this year.

Browser vendors and certificate authorities have been engaged in a coordinated effort to phase out the use of SHA-1 certificates on the web for the past few years, because the hashing function no longer provides sufficient security against spoofing.

SHA-1 (Secure Hash Algorithm 1) dates back to 1995 and has been known to be vulnerable to theoretical attacks since 2005. The U.S. National Institute of Standards and Technology has banned the use of SHA-1 by U.S. federal agencies since 2010, and digital certificate authorities have not been allowed to issue SHA-1-signed certificates since Jan. 1, 2016, although some exemptions have been made -- for example, for outdated payment terminals.

A sophisticated Russian cyberespionage group is readying attacks against Mac users and has recently ported its Windows backdoor program to macOS.

The group, known in the security industry as Snake, Turla or Uroburos, has been active since at least 2007 and has been responsible for some of the most complex cyberespionage attacks. It targets government entities, intelligence agencies, embassies, military organizations, research and academic institutions and large corporations.

"Compared to other prolific attackers with alleged ties to Russia, such as APT28 (Fancy Bear) and APT29 (Cozy Bear), Snake’s code is significantly more sophisticated, it’s infrastructure more complex and targets more carefully selected," researchers from Dutch cybsersecurity firm Fox-IT said in a blog post Wednesday.

The Xen Project has fixed three vulnerabilities in its widely used hypervisor that could allow operating systems running inside virtual machines to access the memory of the host systems, breaking the critical security layer among them.

Two of the patched vulnerabilities can only be exploited under certain conditions, which limits their use in potential attacks, but one is a highly reliable flaw that poses a serious threat to multitenant data centers where the customers' virtualized servers share the same underlying hardware.

The 2017-05-01 security patch level covers fixes for vulnerabilities that are common to all Android devices while the 2017-05-05 level covers additional fixes for hardware drivers and kernel components that are present only in some devices.

Hundreds of thousands of internet gateway devices around the world, primarily residential cable modems, are vulnerable to hacking because of a serious weakness in their Simple Network Management Protocol implementation.

SNMP is used for automated network device identification, monitoring and remote configuration. It is supported and enabled by default in many devices, including servers, printers, networking hubs, switches and routers.

Independent researchers Ezequiel Fernandez and Bertin Bervis recently found a way to bypass SNMP authentication on 78 models of cable modems that ISPs from around the world have provided to their customers.

Users of Webroot's endpoint security product, consumers and businesses alike, had a nasty surprise Monday when the program started flagging Windows files as malicious.

The reports quickly popped up on Twitter and continued on the Webroot community forum -- 14 pages and counting. The company came up with a manual fix to address the issue, but many users still had problems recovering their affected systems.

The problem is what's known in the antivirus industry as a "false positive" -- a case where a clean file is flagged as malicious and is blocked or deleted. False positive incidents can range in impact from merely annoying -- for example, when a program cannot run anymore -- to crippling, where the OS itself is affected and no longer boots.

A 32-year-old Russian hacker was sentenced to 27 years in prison in the U.S. for stealing millions of payment card details from businesses by infecting their point-of-sale systems with malware.

The sentence is the longest ever handed out in the U.S. for computer crimes, surpassing the 20-year jail term imposed on American hacker and former U.S. Secret Service informant Albert Gonzalez in 2010 for similar credit card theft activities.

Roman Valeryevich Seleznev, a Russian citizen from Vladivostok, was sentenced Friday in the Western District of Washington after he was found guilty in August of 10 counts of wire fraud, eight counts of intentional damage to a protected computer, nine counts of obtaining information from a protected computer, nine counts of possession of 15 or more unauthorized access devices and two counts of aggravated identity theft.

Two dozen Linksys router models are vulnerable to attacks that could extract sensitive information from their configurations, cause them to become unresponsive and even completely take them over.

The vulnerabilities were discovered by senior security consultant Tao Sauvage from IOActive and independent security researcher Antide Petit while working together to analyze the Linksys EA3500 Smart Wi-Fi wireless router.

The two researchers found a total of 10 vulnerabilities that affect not only the EA3500, but two dozen different router models from Linksys' Smart Wi-Fi, WRT and Wireless-AC series. Even though these devices are marketed as consumer products, it's not unusual to find them running in small business and home office environments.

Oracle has released a record 299 security fixes for vulnerabilities in its products, including patches for a widely exploited vulnerability in the Apache Struts framework and a Solaris exploit supposedly used by the U.S. National Security Agency.

The Struts vulnerability allows for remote code execution on Java web servers and was patched on March 6. Attackers have quickly adopted it and have used it in widespread attacks since then.

Oracle uses Apache Struts 2 in several of its products, which is why Tuesday’s critical patch update (CPU) fixed 25 instances of the vulnerability in Oracle Communications, Retail and Financial Services applications, as well as in the MySQL Enterprise Monitor, Oracle WebCenter Sites, Oracle WebLogic Server and the Siebel E-Billing app.

In a few months, publicly trusted certificate authorities will have to start honoring a special Domain Name System (DNS) record that allows domain owners to specify who is allowed to issue SSL certificates for their domains.

The Certification Authority Authorization (CAA) DNS record became a standard in 2013 but didn't have much of a real-world impact because certificate authorities (CAs) were under no obligation to conform to them.

The record allows a domain owner to list the CAs that are allowed to issue SSL/TLS certificates for that domain. The reason for this is to limit cases of unauthorized certificate issuance, which can be accidental or intentional, if a CA is compromised or has a rogue employee.

Hackers have started adding data-wiping routines to malware that's designed to infect internet-of-things and other embedded devices. Two attacks observed recently displayed this behavior but likely for different purposes.

Researchers from Palo Alto Networks found a new malware program dubbed Amnesia that infects digital video recorders through a year-old vulnerability. Amnesia is a variation of an older IoT botnet client called Tsunami, but what makes it interesting is that it attempts to detect whether it's running inside a virtualized environment.

Users who have had their files encrypted by any version of the Bart ransomware program are in luck: Antivirus vendor Bitdefender has just released a free decryption tool.

The Bart ransomware appeared back in June and stood out because it locked victims' files inside ZIP archives encrypted with AES (Advanced Encryption Standard). Unlike other ransomware programs that used RSA public-key cryptography and relied on a command-and-control server to generate key pairs, Bart was able to encrypt files even in the absence of an internet connection.

A proof-of-concept exploit has been published for an unpatched vulnerability in Microsoft Internet Information Services 6.0, a version of the web server that's no longer supported but still widely used.

The exploit allows attackers to execute malicious code on Windows servers running IIS 6.0 with the privileges of the user running the application. Extended support for this version of IIS ended in July 2015 along with support for its parent product, Windows Server 2003.

Even so, independent web server surveys suggest that IIS 6.0 still powers millions of public websites. In addition, many companies might still run web applications on Windows Server 2003 and IIS 6.0 inside their corporate networks, so this vulnerability could help attackers perform lateral movement if they access such networks through other means.